The Pumps for Kids, Infants, and Neonates (PumpKIN) clinical trial will explore the potential benefit of therapy offered by a novel pediatric circulatory support device to infants, neonates, and young children (<25 kg) with congenital and acquired cardiovascular disease who experience cardiopulmonary failure and circulatory collapse. The device to be used in the trial, the Infant Jarvik 2015 VAD, has been developed to address many of the known shortcomings of circulatory support devices and designed specifically to provide circulatory support for young children and infants. The trial is intended to provide clinical evidence to be used in a Humanitarian Device Exemption application to the U.S. Food and Drug Administration (FDA) for regulatory approval of the device that has been developed as part of the PumpKIN pre-clinical contract program. This purpose of this task order is to manage the implementation of the Vanguard Phase of the trial at the clinical sites.